Spa alkalinity regulators

• Use strips or a liquid kit (more accurate).
  
• Frequency: 1×/week, and always after a long swim or adding product.
  
  

• Targets: pH 7.2–7.8 · Total alkalinity 100–150 ppm · Calcium hardness 100–200 ppm
  
• Order: Alkalinity → pH → Hardness. Adjust only one parameter at a time. Wait 20-30 minutes between each product.

First, stabilize total alkalinity at 100–150 ppm. Proper alkalinity buffers pH and limits roller coasters. Then, fine-tune pH.

• pH stability: alkalinity “buffers” the pH. Too low = pH roller coaster; too high = pH difficult to lower.
  
• Problem prevention: Correct alkalinity limits corrosion, turbidity and scaling.

• Increase total alkalinity (aim for 100–150 ppm): Use an alkalinity booster (Alca+). With the pump running, add in small doses.
  
• Lower total alkalinity (without upsetting pH):
  
• With the pump stopped, dose a small amount of pH-/acidifier at a single point (near a drain if possible).
  
• Then aerate (jets/bubbles) to raise the pH without raising the total alkalinity too much.
  
• Retest and repeat in stages.
  
• Symptoms of out-of-range total alkalinity:
  
• Too low (<100 ppm) → unstable pH, “aggressive” water, risk of corrosion, irritation.
  
• Too high (>150 ppm) → pH difficult to lower, cloudy water, limescale deposits.
  
• Tip: Adjust only one product at a time, follow the label, and respect the balancing order total alkalinity → pH → hardness.

Total alkalinity is the buffering capacity of water: it stabilizes pH and prevents sudden changes. The target in spas is 100–150 ppm. Below this, pH becomes unstable and the water can become aggressive to surfaces and metals; above this, pH becomes difficult to lower and cloudiness/scale may appear.